Multi-layer shell tank and ship

Abstract

The multi-layer shell tank is provided with: an inner tank for accommodating liquefied gas; an outer tank surrounding the inner tank; and a dome which is engaged with the inner groove and the outer groove, and which has a portion protruding in a protruding direction from the outer groove. The dome has: a first main body part joined to the inner groove; a second body portion disposed apart from the first body portion in the protruding direction and joined to the outer groove; and a connecting part that connects the first body part and the second body part and is elastically deformable in accordance with the relative displacement of the first body part with respect to the second body part, the inner peripheral space of the first body part, the inner peripheral space of the connecting part, and the inner peripheral space of the second body part communicating with each other.

Description

Technical Field

[0001] The present disclosure relates to a multi-layer hull tank and a ship having the multi-layer hull tank. Background Art

[0002] In the past, a multilayer shell tank is known as a container for storing low-temperature liquids such as liquefied gas. Such a multilayer shell tank has an inner tank and at least one outer tank surrounding the inner tank, and a heat-proof layer is provided between the tanks to suppress heat input to the inner tank. Patent document 1 discloses such a multilayer shell tank.

[0003] The double-shell tank disclosed in Patent Document 1 is carried on a liquefied gas transport ship. The double-shell tank has an inner tank and an outer tank. The inner tank has an inner tank body for storing liquefied gas and an inner tank top protruding upward from the inner tank body. The outer tank has an outer tank body surrounding the inner tank body and an outer tank top surrounding the inner tank top. Through portions for various pipes such as liquefied gas transfer piping and electrical piping are centrally arranged at the inner tank top and the outer tank top. The inner tank top and the outer tank top are connected by a connecting member, thereby connecting the inner tank and the outer tank.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-4383 Summary of the invention

[0007] Problems to be solved by the invention

[0008] As in Patent Document 1, when the inner tank is completely surrounded by the outer tank, the inner and outer access paths connecting the outer tank and the inner tank pass through the outer tank and the inner tank, and the inner tank can only be opened after gas purification between the inner and outer tanks. In view of such a situation, it is desirable to have a multi-layer shell tank having an inner and outer access path that does not pass through the inner and outer tanks.

[0009] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a structure in which internal and external access paths can be simplified in a structure having a multilayer shell tank having an inner tank and an outer tank surrounding the inner tank and having a dome in which piping and the like are centrally arranged.

[0010] Means for solving problems

[0011] In order to solve the above-mentioned problems, a multilayer shell tank of one embodiment of the present invention comprises: an inner tank, which accommodates liquefied gas; an outer tank, which surrounds the inner tank; and a dome, which is connected to the inner tank and the outer tank, and a part of which protrudes from the outer tank in a protruding direction, and the dome comprises: a first main body, which is connected to the inner tank; a second main body, which is separated from the first main body along the protruding direction and connected to the outer tank; and a connecting part, which connects the first main body and the second main body, and can elastically deform following the relative displacement of the first main body with respect to the second main body, and the inner peripheral space of the first main body, the inner peripheral space of the connecting part, and the inner peripheral space of the second main body are connected.

[0012] Furthermore, a ship according to one aspect of the present disclosure includes a hull and the multilayer hull tank supported by the hull.

[0013] Effects of the Invention

[0014] According to the present disclosure, in a structure of a multilayer shell tank having an inner tank and an outer tank surrounding the inner tank and having a dome in which pipes and the like are centrally arranged, it is possible to simplify the access path inside and outside the tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic vertical cross-sectional view of a ship having a multi-layer hull tank according to an embodiment of the present disclosure.

[0016] Figure 2 is an enlarged vertical cross-sectional view of the top of a multi-layer shell tank.

[0017] Figure 3 This is an enlarged cross-sectional view of the top of the multilayer shell tank of Modification Example 1.

[0018] Figure 4 This is a diagram for explaining the dimensions of each part of the connection portion.

[0019] Figure 5 is an enlarged vertical cross-sectional view of the top of a multi-layer shell tank after deformation.

[0020] Figure 6 This is an enlarged cross-sectional view of the top of the multilayer shell can showing the deformation allowing portion of Modification Example 1.

[0021] Figure 7 It is an enlarged cross-sectional view of the top of the multilayer shell can showing the deformation allowing portion of Modification Example 2.

[0022] Figure 8 It is an enlarged cross-sectional view of the top of the multilayer shell can showing the deformation allowing portion according to Modification Example 3.

[0023] Fig. 9 It is an enlarged cross-sectional view of the top of the multilayer shell can showing the deformation allowing portion according to Modification Example 4. DETAILED DESCRIPTION

[0024] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, in this specification, "inner side" refers to the side close to the center of the space in the inner tank 3 of the multilayer shell tank 2, and "outer side" refers to the side away from the center of the space in the inner tank 3 of the multilayer shell tank 2.

[0025] Figure 1 FIG. 1 is a schematic vertical cross-sectional view of a ship 1 having a multi-layer hull tank 2 according to an embodiment of the present disclosure. Figure 1 As shown, the ship 1 has at least one multilayer shell tank 2 and a hull 11 supporting the multilayer shell tank 2. Cryogenic liquefied gas is stored in the multilayer shell tank 2. Examples of liquefied gas include LNG, liquefied nitrogen, liquefied hydrogen, and liquefied helium. The ship 1 is a liquefied gas transport ship that transports liquefied gas. The multilayer shell tank 2 of this embodiment is a loading and unloading tank that stores liquefied gas as cargo, but the multilayer shell tank 2 may also be a fuel tank.

[0026] [Schematic structure of multilayer shell tank 2]

[0027] The multilayer shell tank 2 has an inner groove 3, an outer groove 4 surrounding the inner groove 3, and a dome 6 that penetrates the inner groove 3 and the outer groove 4 along a protruding direction X. In the present embodiment, the protruding direction X is the up and down direction. The multilayer shell tank 2 of the present embodiment has two layers of grooves, the inner groove 3 and the outer groove 4, but the multilayer shell tank 2 may also have more than three layers of grooves. The outer groove 4 is surrounded by a tank cover 12 covering the upper part and a retaining wall 14 covering the side and the bottom. The retaining space 53 between the outer groove 4 and the tank cover 12 and the retaining wall 14 is filled with air or an inert gas. The top of the dome 6 protrudes upward from the tank cover 12 and is exposed.

[0028] The inner tank 3 is a storage container for liquefied gas, and has a storage space 51 for storing liquefied gas therein. A pipe tower 20 extending in the protruding direction X is arranged in the storage space 51. A pump 21 is arranged at the bottom of the pipe tower 20. The upper part of the pipe tower 20 is joined to the lower part of the dome 6. The top of the inner tank 3 is joined to the inner tank joint 61 of the dome 6. In addition, the top of the outer tank 4 is joined to the outer tank joint 62 of the dome 6. The outer tank joint 62 is located above the inner tank joint 61.

[0029] The inner tank 3 and the outer tank 4 are separated in the radial direction of the multilayer shell tank 2. An airtight inner and outer tank space 52 is formed between the inner tank 3 and the outer tank 4, and a heat-proof layer made of a heat-insulating material or the like is arranged in the inner and outer tank space 52. The inner and outer tank space 52 is filled with an inter-tank gas. The inter-tank gas is, for example, a gas having a boiling point higher than the boiling point of the liquefied gas stored in the storage space 51. In the present embodiment, the vaporized gas of the liquefied gas in the storage space 51 is used as the inter-tank gas. In this way, when the gas filled in the storage space 51 and the inner and outer tank space 52 is the same, the inner and outer tank space 52 can also be connected to the inner and outer tank space 52 in the inner tank 3.

[0030] [Structure of the top of the multilayer shell tank 2]

[0031] Figure 2 2 is an enlarged vertical cross-sectional view of the top of the multi-layer shell tank 2. Figure 2 As shown, the dome 6 includes a first body portion 65 , a second body portion 66 , a roof portion 67 , and a connecting portion 68 .

[0032] The first main body 65 has a cylindrical shape, and an inner groove joint portion 61 is provided on the first main body 65. The inner groove 3 is joined to the inner groove joint portion 61, and the movement of the first main body 65 is constrained by the inner groove 3. The second main body 66 has a cylindrical shape, and an outer groove joint portion 62 is provided on the second main body 66. The outer groove 4 is joined to the outer groove joint portion 62, and the movement of the second main body 66 is constrained by the outer groove 4. The upper part of the second main body 66 is closed by the roof portion 67. In the present embodiment, the first main body 65 and the second main body 66 are cylindrical, but it is not limited to this, and the first main body 65 and the second main body 66 only need to be cylindrical. The second main body 66 is arranged above the first main body 65, and the first main body 65 and the second main body 66 are separated in the protruding direction X. The gap between the first main body 65 and the second main body 66 is connected to the inner and outer grooves 52 of the inner groove 3 and the outer groove 4.

[0033] The connecting portion 68 connects the first main body portion 65 and the second main body portion 66 in a manner that allows relative displacement of the first main body portion 65 constrained by the inner groove 3 and the second main body portion 66 constrained by the outer groove 4. The entirety or a portion of the connecting portion 68 is disposed inside the dome 6. The connecting portion 68 includes a first annular plate 71, a second annular plate 72, and a cylinder 73. The connecting portion 68 is interposed between the inner groove 3 and the outer groove 4, and transmits load between the inner groove 3 and the outer groove 4.

[0034] The first annular plate 71 is a hollow circular flat plate having an outer diameter substantially the same as or slightly smaller than that of the first main body 65. The first annular plate 71 has a main surface that is substantially perpendicular to the protruding direction X when the first annular plate 71 is not deformed. The outer edge of the first annular plate 71 is joined to the upper end of the first main body 65. The outer edge of the first annular plate 71 may also be joined to the inner peripheral surface of the first main body 65. Since the movement of the first main body 65 is constrained by the inner groove 3, the movement of the outer edge of the first annular plate 71 is also constrained by the inner groove 3.

[0035] The second annular plate 72 is a hollow circular flat plate having an outer diameter substantially the same as or slightly smaller than that of the second main body 66. The second annular plate 72 has a main surface that is substantially perpendicular to the protruding direction X when the second annular plate 72 is not deformed. The outer edge of the second annular plate 72 is joined to the inner peripheral surface of the second main body 66. The outer edge of the second annular plate 72 may also be joined to the lower end of the second main body 66. Since the movement of the second main body 66 is restricted by the outer groove 4, the movement of the outer edge of the second annular plate 72 is also restricted by the outer groove 4.

[0036] The first annular plate 71 and the second annular plate 72 are separated from each other in the protruding direction X. Figure 2 In the example shown, since the first body portion 65 and the second body portion 66 have substantially the same outer diameter, the first annular plate 71 and the second annular plate 72 have substantially the same outer diameter. However, the first body portion 65 and the second body portion 66 may have different outer diameters, and the first annular plate 71 and the second annular plate 72 may have different outer diameters.

[0037] The cylinder 73 is a cylindrical member extending in the protruding direction X. The outer diameter of the cylinder 73 is smaller than the inner diameter of the first main body 65 and the second main body 66, and the cylinder 73 is arranged inside the first main body 65 and the second main body 66. The outer diameter of the cylinder 73 is substantially the same as the inner diameter of the first annular plate 71 and the inner diameter of the second annular plate 72. The inner edge of the first annular plate 71 and the inner edge of the second annular plate 72 separated in the protruding direction X are connected by the cylinder 73.

[0038] As described above, the connecting portion 68 formed by the first annular plate 71, the cylinder 73 and the second annular plate 72 is C-shaped with a cross section parallel to the protruding direction X open toward the outer peripheral side. By having such a shape of the connecting portion 68, the connecting portion 68 suppresses the radial dimension and has a higher elastic deformation capacity. However, it is also possible that the outer diameter of the first annular plate 71 is substantially the same as the inner diameter of the second annular plate 72, the outer edge of the first annular plate 71 is connected to the inner edge of the second annular plate 72 by the cylinder 73, and the connecting portion 68 having a crank-shaped cross section parallel to the protruding direction X is formed by the first annular plate 71, the cylinder 73 and the second annular plate 72. Alternatively, in the connecting portion 68, the inner diameter of the first annular plate 71 is substantially the same as the outer diameter of the second annular plate 72, the inner edge of the first annular plate 71 and the outer edge of the second annular plate 72 are connected by the cylinder 73, and a connecting portion 68 having a crank-shaped cross-section parallel to the protruding direction X is formed by the first annular plate 71, the cylinder 73 and the second annular plate 72.

[0039] The upper end of the cylinder 73 is joined to the inner edge of the second annular plate 72, and the lower end of the cylinder 73 is joined to the inner edge of the first annular plate 71. In this way, the cylinder 73 is joined to the first annular plate 71 and the second annular plate 72 in a substantially perpendicular manner in the vertical cross section of the multilayer shell tank 2. However, the corner of the connection between the cylinder 73 and at least one of the first annular plate 71 and the second annular plate 72 may be rounded.

[0040] exist Figure 3 In the modified example of the multilayer shell tank 2 shown, the cylinder 73 and the first annular plate 71 are connected via a ring member 70 whose vertical cross section is an arc. As a result, the cross section of the connection between the cylinder 73 and the first annular plate 71 in the protruding direction X becomes a smooth curve, which suppresses the concentration of stress on the connection. Similarly, the cylinder 73 and the second annular plate 72 are connected via a ring member 70 whose cross section in the protruding direction X is an arc. As a result, the vertical cross section of the connection between the cylinder 73 and the second annular plate 72 becomes a smooth curve, which suppresses the concentration of stress on the connection. In addition, Figure 3 In the example shown, the first annular plate 71 and the first main body 65 are connected via a ring member 70 having an arc-shaped cross section in the protruding direction X. In this way, the corners of the connection portion between the connecting portion 68 and the first main body 65 or the second main body 66 may be rounded.

[0041] return Figure 2, the first annular plate 71 is arranged between the inner groove joint part 61 and the outer groove joint part 62 in the protruding direction X. Thus, the outer peripheral space 74 of the cylinder 73 surrounded by the first annular plate 71, the second annular plate 72 and the cylinder 73 is communicated with the inner and outer grooves 52. In addition, in the present embodiment, the second annular plate 72 is arranged at a position farther from the inner groove joint part 61 than the outer groove joint part 62 in the protruding direction X. Thus, the outer peripheral space 74 of the cylinder 73 has an area separated from the exposed space or the holding space 53 only by the second main body 66 of the dome 6.

[0042] The outer peripheral space 74 communicating with the inner and outer slots 52 can be used as a wiring space for the slot piping 92 (or slot wiring) passing through the inner and outer slots 52. Figure 1 As shown, the inter-tank piping 92 is guided from the inner and outer tanks 52 to the outer peripheral space 74 of the cylinder 73, and is guided to the exposed space through the through-portion of the second main body 66 of the dome 6. That is, the inter-tank piping 92 does not pass through the storage space 51 and the holding space 53, but passes through the inner and outer tanks 52 and the space communicating with the inner and outer tanks 52 and is directly guided to the exposed space. In addition, the through-portion through which the inter-tank piping 92 passes in the dome 6 can be subjected to airtight construction for ensuring the airtightness of the inner and outer tanks 52, and heat-proof construction similar to the tank. Instead of the inter-tank piping 92 or on the basis of the inter-tank piping 92, the inter-tank wiring can be laid in the same manner as the inter-tank piping 92. In addition, inside the dome 6, the inner peripheral space of the first main body 65, the inner peripheral space of the connecting portion 68, and the inner peripheral space of the second main body 66 (except for the portion where the connecting portion 68 exists on the inner peripheral side) are connected, forming a space extending in the protruding direction X. The in-tank pipe 91 passing through the pipe tower 20 passes through the space extending in the protruding direction X inside the dome 6 communicating with the pipe tower 20, passes through the second main body 66 or the roof 67 of the dome 6, and is guided to the exposed space. Instead of the in-tank pipe 91 or in addition to the in-tank pipe 91, in-tank wiring may be laid in the same manner as the in-tank pipe 91. In this way, the through-portions of the in-tank pipe 91 and the inter-tank pipe 92 are collectively arranged in the dome 6, and the in-tank pipe 91 and the inter-tank pipe 92 are respectively guided to the outside of the tank through one through-portion arranged in the dome 6.

[0043] return Figure 2The cylinder 73 has a first cylinder portion 731, a second cylinder portion 732, and a deformation-allowing portion 7 disposed between the first cylinder portion 731 and the second cylinder portion 732. The deformation-allowing portion 7 can elastically deform following the relative displacement of the second cylinder portion 732 relative to the first cylinder portion 731. The deformation-allowing portion 7 is composed of a combination of a plurality of ring plates 7a or a combination of a ring plate 7a and a third cylinder portion 7b. The ring plate 7a is a hollow circular flat plate-shaped component having a main surface that is substantially perpendicular to the protruding direction X when non-deformed. The third cylinder portion 7b is a cylindrical component that extends substantially parallel to the protruding direction X. The thinner the thickness of the ring plate 7a, the more the flexibility of the ring plate 7a is improved, but the ring plate 7a must ensure a thickness that can transmit the load. The ring plate 7a and the third cylinder portion 7b have a plate thickness of, for example, more than 10 mm and less than 60 mm. The cylindrical body 73 including such a deformation allowing portion 7 can still transmit the load between the first annular plate 71 and the second annular plate 72 .

[0044] The deformation allowing portion 7 is composed of a pair of ring plates 7a separated and arranged in the protruding direction X and a third tube portion 7b connecting the pair of ring plates 7a in the protruding direction X. The inner edge portions of the pair of ring plates 7a are joined to the cylinder 73. The outer edge portions of the pair of ring plates 7a are joined to the third tube portion 7b. Preferably, the pair of ring plates 7a are joined in a manner that the third tube portion 7b is sandwiched between them.

[0045] The arrangement of the deformation-allowing portion 7 in the cylinder 73 is not particularly limited, but it is preferred that the joints of the components are not extremely close to each other. Figure 4 As shown, the first end 73a of the cylinder 73 joined to the first annular plate 71 is separated from the deformation allowing portion 7 by H1 in the protruding direction X. H1 is a value indicating the degree to which the joint between the first annular plate 71 and the cylinder 73 is not narrow, and although it is not particularly limited, it is 500 mm or more. The second end 73b of the cylinder 73 joined to the second annular plate 72 is separated from the deformation allowing portion 7 by H2 in the protruding direction X. H2 is a value indicating the degree to which the joint between the second annular plate 72 and the cylinder 73 is not narrow, and although it is not particularly limited, it is 500 mm or more.

[0046] The dimension of the third tube portion 7b in the protruding direction X, that is, the separation distance between the pair of ring plates 7a is H3. H3 is a value that does not narrow the joint between the ring plate 7a and the third tube portion 7b, and is not particularly limited, but is 500 mm or more.

[0047] The greater the difference between the outer diameter and the inner diameter of the ring plate 7a, the more the flexibility of the ring plate 7a is improved. However, in order to prevent an extremely narrow portion from existing in the outer peripheral space 74 of the cylinder 73, the outer wall of the cylinder 73 including the deformation-allowing portion 7 and the inner wall of the second main body 66 of the dome 6 are separated by R1 in the radial direction. In the case where the deformation-allowing portion 7 protrudes from the other parts of the cylinder 73 to the radial outside of the dome 6, the maximum diameter of the cylinder 73 is the outer diameter of the ring plate 7a of the deformation-allowing portion 7. R1 is a value of the degree to which the outer peripheral space 74 of the cylinder 73 is not extremely narrow and can be passed by an operator, piping, and wiring, and although it is not particularly limited, it is 500 mm or more.

[0048] In the multilayer shell tank 2 of the above structure, when liquefied gas is stored in the storage space 51 of the inner tank 3, the inner tank 3 and the outer tank 4 shrink due to the heat and cold thereof. Here, since the temperature of the inner tank 3 is lower than that of the outer tank 4, the inner tank 3 shrinks thermally to a greater extent than the outer tank 4. As a result, relative displacement occurs between the inner tank joint portion 61 to which the inner tank 3 is joined and the outer tank joint portion 62 to which the outer tank 4 is joined in the dome 6. Figure 5 This is a diagram showing a state in which the inner groove joint portion 61 and the outer groove joint portion 62 are relatively displaced due to thermal contraction. However, the deformation of the connecting portion 68 and the inner groove 3 is exaggeratedly shown.

[0049] like Figure 5 As shown, when the inner groove 3 and the outer groove 4 shrink by heat, the interval between the inner groove joint 61 constrained by the inner groove 3 and the outer groove joint 62 constrained by the outer groove 4 increases. Along with this, the connecting portion 68 of the dome 6 is stretched in the protruding direction X as a whole, and the stress generated by the relative displacement of the inner groove joint 61 and the outer groove joint 62 is absorbed. In detail, the first annular plate 71, the second annular plate 72 and the annular plate 7a of the cylinder 73 in the connecting portion 68 are elastically deformed in a manner that the outer edge and the inner edge are separated in the protruding direction X, thereby the connecting portion 68 is stretched in the protruding direction X as a whole.

[0050] The structure of the deformation allowing portion 7 of the cylindrical body 73 is not limited to the above structure, and any structure may be used as long as the cylindrical body 73 can be extended in the protruding direction X by elastic deformation. Hereinafter, a modification example of the cylindrical body 73 will be described.

[0051] (Variant 1)

[0052] Figure 2 The deformation allowing portion 7 of the illustrated cylindrical body 73 protrudes toward the outer diameter side relative to the main body of the cylindrical body 73. However, the deformation allowing portion 7 may protrude toward the inner diameter side relative to the main body of the cylindrical body 73. Figure 6The deformation-allowing portion 7 of the cylinder 73 of the modified example shown has a pair of ring plates 7a that join the cylinder 73 to the outer edge and a third cylinder 7b that connects the inner edge of the pair of ring plates 7a. The inner diameter of the cylinder 73 including the deformation-allowing portion 7 is a value that allows the inner circumference of the cylinder 73 to be not narrow and allows the pump 21, piping, and wiring to pass through, and is not particularly limited, but is 1000 mm or more. Figure 6 In the example shown, the minimum diameter of the cylinder 73 is the inner diameter of the ring plate 7a of the deformation allowing portion 7, and the ring plate 7a has an inner diameter of 1000 mm or more.

[0053] (Variant 2)

[0054] Figure 2 The illustrated cylindrical body 73 has one deformation allowing portion 7 , but may have a plurality of deformation allowing portions 7 separated in the protruding direction X. Figure 7 The cylinder 73 of the modified example shown has two deformation allowing portions 7. The two deformation allowing portions 7 are separated by H4 in the protruding direction X. H4 is a value to prevent the joint between the ring plate 7a and the main body of the cylinder 73 from being narrow, and is not particularly limited but is 500 mm or more.

[0055] (Variant 3)

[0056] Figure 2 The deformation allowing portion 7 of the illustrated cylindrical body 73 is composed of a pair of ring plates 7a and a third cylindrical portion 7b, but the third cylindrical portion 7b may be omitted. Figure 8 The deformation-allowing portion 7 of the cylinder 73 of the modified example shown is composed of a pair of ring plates 7a whose inner edges are joined to each other. The outer edges of the pair of ring plates 7a are both joined to the main body of the cylinder 73. However, the deformation-allowing portion 7 may also be composed of a pair of ring plates 7a whose outer edges are joined to each other.

[0057] (Variant 4)

[0058] Figure 2 The deformation allowing portion 7 of the illustrated cylindrical body 73 is composed of a pair of ring plates 7 a and the third cylindrical portion 7 b , but the deformation allowing portion 7 only needs to be able to transmit the load and to be able to elastically expand and contract in the protruding direction X. Fig. 9 The deformation-allowing portion 7 of the cylinder 73 of the modified example shown is a protrusion 7c having a curved cross section in the protruding direction X and protruding inward or outward from the first cylinder 731 and the second cylinder 732. The protrusion 7c is continuous in the circumferential direction on the surface of the cylinder 73. The cross section of the protrusion 7c may also be wavy, and the deformation-allowing portion 7 may also be composed of a bellows, for example.

[0059] 〔Summarize〕

[0060] The multilayer shell tank 2 of the first item of the present disclosure comprises: an inner tank 3, which accommodates liquefied gas; an outer tank 4, which surrounds the inner tank 3; and a dome 6, which is connected to the inner tank 3 and the outer tank 4, and a part of which protrudes from the outer tank 4 along the protruding direction X, and the dome 6 comprises: a first main body 65, which is connected to the inner tank 3; a second main body 66, which is separated from the first main body 65 along the protruding direction X and connected to the outer tank 4; and a connecting portion 68, which connects the first main body 65 and the second main body 66, and can elastically deform following the relative displacement of the first main body 65 relative to the second main body 66, and the inner peripheral space of the first main body 65, the inner peripheral space of the connecting portion 68 and the inner peripheral space of the second main body 66 are connected.

[0061] The multilayer shell tank 2 of the second item of the present disclosure is based on the multilayer shell tank 2 of the first item, wherein the connecting portion 68 includes: a first annular plate 71, which has an outer edge portion connected to the first main body portion 65; a second annular plate 72, which is arranged separately from the first annular plate 71 along the protruding direction X and has an outer edge portion connected to the second main body portion 66; and a cylindrical body 73, which extends along the protruding direction X and has a first end portion 73a connected to the inner edge portion of the first annular plate 71 and a second end portion 73b connected to the inner edge portion of the second annular plate 72.

[0062] According to the multilayer shell tank 2 of the first and second items, the inner tank 3 and the outer tank 4 are connected via the dome 6, so a part of the dome 6 is not surrounded by the outer tank 4. Therefore, the inner tank 3 is accessed through the wall of the dome 6 instead of the wall of the outer tank 4, thereby realizing a simple internal and external access path that does not pass through the inner and outer tanks 52. In addition, in the multilayer shell tank 2 of the above structure, the first main body 65, the connecting part 68, and the space extending along the protruding direction X on the inner periphery of the connecting part 68 are formed, so that the space can be used for wiring or piping in the dome 6. The piping or wiring passing through the dome 6 can be led out to the exposed space through the roof part 67 or the second main body 66 of the dome 6, so that a simple piping or wiring path with a reduced number of penetration points can be formed. Moreover, according to the multilayer shell tank 2 with the above structure, when low-temperature liquefied gas is stored in the inner tank 3 and the degree of thermal shrinkage of the inner tank 3 and the outer tank 4 differs and the inner tank 3 is relatively displaced with respect to the outer tank 4, elastic deformation occurs mainly in the first annular plate 71 and the second annular plate 72 in the connecting portion 68, and the stress generated by the above relative displacement is suppressed.

[0063] The multilayer shell tank 2 of the third item of the present disclosure is based on the multilayer shell tank 2 of the second item, wherein the cylinder 73 includes a first cylinder portion 731 and a second cylinder portion 732 separated and arranged in the protruding direction X, and a deformation allowing portion 7 that can elastically deform following the relative displacement of the second cylinder portion 732 relative to the first cylinder portion 731.

[0064] According to the multilayer shell tank 2 of the above structure, when the inner tank 3 is relatively displaced with respect to the outer tank 4, the connecting portion 68 is deformed following the relative displacement of the inner tank 3 with respect to the outer tank 4 by elastic deformation of the first annular plate 71 and the second annular plate 72 and elastic deformation of the deformation allowing portion 7. By increasing the elastic deformation sites in the connecting portion 68, the connecting portion 68 can be elastically deformed more greatly and softly.

[0065] The multilayer shell tank 2 according to claim 4 of the present disclosure is the multilayer shell tank 2 according to claim 3, wherein the deformation allowing portion 7 includes a pair of ring plates 7a spaced apart from each other in the protruding direction X and a third tube portion 7b connecting the pair of ring plates 7a.

[0066] The multilayer shell can 2 according to claim 5 of the present disclosure is the multilayer shell can 2 according to claim 3, wherein the deformation allowing portion 7 includes a pair of ring plates 7a whose outer edge portions or inner edge portions are joined to each other.

[0067] The multilayer shell can 2 according to claim 6 of the present disclosure is the multilayer shell can 2 according to claim 3, wherein the deformation allowing portion 7 includes a protrusion 7 c having a curved cross section in the protruding direction X and continuous in the circumferential direction on the surface of the cylinder 73 .

[0068] According to the multilayer shell tank 2 of the fourth to sixth items, the deformation allowing portion 7 capable of transmitting the load in the cylinder 73 can be easily configured.

[0069] The multilayer shell tank 2 according to item 7 of the present disclosure is the multilayer shell tank 2 according to any one of items 2 to 6, wherein the corner of the connection portion between at least one of the first annular plate 71 and the second annular plate 72 and the cylinder 73 is rounded.

[0070] The multilayer shell tank 2 according to an eighth aspect of the present disclosure is the multilayer shell tank 2 according to the seventh aspect, wherein the annular plate and the cylinder 73 are connected via a ring member 70 whose cross section in the protruding direction X is curved.

[0071] According to the multilayer shell tank 2 of the seventh and eighth aspects, it is possible to suppress the concentration of stress on the connection portion between the annular plates 71 and 72 and the cylindrical body 73 .

[0072] The multilayer shell tank 2 of item 9 of the present disclosure is a multilayer shell tank 2 according to any item from item 2 to item 8, wherein an outer peripheral space 74 communicating with the inner and outer grooves 52 of the inner groove 3 and the outer groove 4 is provided between the inner wall of the second main body portion 66 and the outer wall of the cylinder 73 .

[0073] Thus, by providing a space communicating with the inner and outer grooves 52 , namely, the outer peripheral space 74 inside the dome 6 , it is possible to access the inner and outer grooves 52 through the wall of the dome 6 instead of through the wall of the outer groove 4 .

[0074] The multilayer shell tank 2 of item 10 of the present disclosure is based on the multilayer shell tank 2 of item 9, wherein the second main body 66 has a through portion connecting the peripheral space 74 with the exposed space, and the multilayer shell tank 2 has an inter-groove piping 92 that passes through the inner and outer grooves 52, the peripheral space 74 and the through portion.

[0075] In the above-described multilayer shell tank 2 , the inter-tank pipe 92 can be extended to the exposed space through the through-portion of the wall of the dome 6 without passing through the wall of the outer tank 4 .

[0076] The multilayer shell tank 2 according to the 11th item of the present disclosure is the multilayer shell tank 2 according to the 9th item or the 10th item, wherein the inner wall of the second main body 66 and the outer wall of the cylinder 73 are separated so that an operator can communicate in the outer peripheral space 74 .

[0077] In the multilayer shell tank 2 described above, the outer peripheral space 74 can be used as a passage for workers to communicate.

[0078] The multilayer shell tank 2 of item 12 of the present disclosure is a multilayer shell tank 2 according to any item from item 2 to item 11, wherein the multilayer shell tank 2 also has a tube tower 20 arranged in the inner tank 3 and connected to the lower part of the dome 6, and a pump 21 arranged at the lower part of the tube tower 20, and the cylinder 73 has an inner diameter that allows the pump 21 to pass through.

[0079] In the multilayer shell tank 2 , the pump 21 can be moved in and out of the lower portion of the tube tower 20 through the dome 6 .

[0080] A ship 1 according to a thirteenth aspect of the present disclosure includes a hull 11 and a multilayer hull tank 2 according to any one of the first to twelfth aspects supported by the hull 11 .

[0081] The above-mentioned multilayer shell tank 2 is suitable as a loading and unloading tank or a fuel tank carried on the ship 1.

[0082] The above discussion of the present disclosure is presented for the purpose of illustration and description, and is not intended to limit the present disclosure to the methods disclosed in this specification. For example, in the above detailed description, various features of the present disclosure are summarized into one embodiment for the purpose of rationalizing the present disclosure, but several of the multiple features may be combined. In addition, the multiple features included in the present disclosure may also be combined with alternative embodiments, structures or methods other than those described above.

Claims

1. A multilayer shell tank, comprising: an inner tank for storing liquefied gas; an outer tank surrounding the inner tank; as well as a dome that engages with the inner groove and the outer groove and has a portion that protrudes from the outer groove in a protruding direction, The dome has: a first main body portion engaged with the inner groove; a second main body portion, which is disposed apart from the first main body portion along the protruding direction and is engaged with the outer groove; as well as a connecting portion connecting the first main body portion and the second main body portion and capable of elastically deforming following a relative displacement of the first main body portion with respect to the second main body portion, The inner peripheral space of the first main body portion, the inner peripheral space of the connecting portion, and the inner peripheral space of the second main body portion are in communication with each other.

2. The multilayer shell tank according to claim 1, wherein: The connecting portion comprises: a first annular plate having an outer edge portion joined to the first main body portion; a second annular plate which is arranged apart from the first annular plate in the protruding direction and has an outer edge portion joined to the second main body portion; and The cylindrical body extends in the protruding direction and has a first end connected to the inner edge of the first annular plate and a second end connected to the inner edge of the second annular plate.

3. The multilayer shell tank according to claim 2, wherein: The cylinder comprises: a first cylindrical portion and a second cylindrical portion, the first cylindrical portion and the second cylindrical portion being arranged to be separated from each other in the protruding direction; and The deformation allowing portion is capable of elastically deforming following the relative displacement of the second tube portion with respect to the first tube portion.

4. The multilayer shell tank according to claim 3, wherein: The deformation allowing portion includes a pair of ring plates that are spaced apart from each other in the protruding direction, and a third cylindrical portion that connects the pair of ring plates.

5. The multi-layer shell tank according to claim 3, wherein: The deformation allowing portion includes a pair of ring plates whose outer edge portions or inner edge portions are joined to each other.

6. The multi-layer shell tank according to claim 3, wherein: The deformation allowing portion includes a protrusion having a curved cross section in the protruding direction and continuous in the circumferential direction on the surface of the cylindrical body.

7. The multilayer shell tank according to any one of claims 2 to 6, wherein: A corner of a connection portion between at least one of the first annular plate and the second annular plate and the cylindrical body is rounded.

8. The multi-layer shell tank according to claim 7, wherein: The annular plate and the cylindrical body are connected via a ring member having a curved cross section in the protruding direction.

9. The multilayer shell tank according to any one of claims 2 to 8, wherein: An outer peripheral space communicating with the inner groove and the outer groove of the outer groove is provided between the inner wall of the second main body and the outer wall of the cylindrical body.

10. The multi-layer shell tank according to claim 9, wherein: The second main body has a through portion that connects the outer peripheral space and the exposed space. The multilayer shell tank has an inter-tank pipe passing through the inner and outer tanks, the outer peripheral space, and the through-portion.

11. The multilayer shell tank according to claim 9 or 10, wherein: The inner wall of the second main body portion and the outer wall of the cylindrical body are separated from each other so that an operator can communicate in the outer peripheral space.

12. The multilayer shell tank according to any one of claims 2 to 11, wherein: The multi-layer shell tank also has: a pipe tower disposed in the inner tank and connected to the lower portion of the dome; and A pump is arranged at the lower part of the tube tower, The cylinder has an inner diameter through which the pump can pass.

13. A vessel having: Hull; and A multilayer tank according to any one of claims 1 to 12 supported on the hull.

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